Method, apparatus and system for performing proxy transformation

Abstract

A method for performing proxy transformation between a user and a server includes: selecting a first proxy relationship between a target user and a first user from a proxy relationship library; selecting a random value, and generating a second proxy relationship according to the random value and the first proxy relationship; and encrypting original information according to the public key of the first user and the random value to obtain the encrypted information, and transmitting the encrypted information and the second proxy relationship to the server, so that the server performs proxy transformation on the encrypted information according to the second proxy relationship to obtain the transformed information. The method for performing proxy transformation thoroughly solves the security hazard that the server performs proxy transformation without user permission. The present invention further discloses a user terminal and a system for performing proxy transformation.

What is claimed is: 
     
       1. A method for performing proxy transformation, comprising:
 selecting a first proxy relationship between a target user and a first user from a proxy relationship library; 
 selecting a random value, and generating a second proxy relationship according to the random value and the first proxy relationship; and 
 encrypting original information according to a public key of the first user and the random value to obtain encrypted information, and transmitting the encrypted information and the second proxy relationship to a server, so that the server performs proxy transformation on the encrypted information according to the second proxy relationship to obtain transformed information. 
 
     
     
       2. The method for performing proxy transformation according to  claim 1 , wherein the first proxy relationship is calculated according to the private key of the first user and the public key of the target user. 
     
     
       3. The method for performing proxy transformation according to  claim 1 , wherein the proxy relationship library is saved at the first user. 
     
     
       4. The method for performing proxy transformation according to  claim 1 , wherein the encrypting the original information according to the public key of the first user and the random value to obtain the encrypted information comprises:
 selecting, by the first user, a symmetric key, and encrypting the original information according to the symmetric key to obtain an initial ciphertext; and 
 encrypting the symmetric key according to the random value and the public key of the first user to obtain encrypted key information, where 
 the encrypted information comprises the initial ciphertext and the encrypted key information. 
 
     
     
       5. The method for performing proxy transformation according to  claim 1 , wherein after the server performs proxy transformation on the encrypted information according to the second proxy relationship to obtain the transformed information, the method further comprises:
 transmitting, by the server, the transformed information to the target user. 
 
     
     
       6. The method for performing proxy transformation according to  claim 5 , wherein after the transmitting, by the server, the transformed information to the target user, the method further comprises:
 decrypting, by the target user, the transformed information according to the private key of the target user to obtain the original information. 
 
     
     
       7. A user terminal for performing proxy transformation, comprising:
 a memory; and 
 a processor coupled to the memory and configured to:
 select a first proxy relationship between the user terminal and a target user terminal from a proxy relationship library, and generate a second proxy relationship according to a random value and the first proxy relationship; 
 encrypt original information to obtain encrypted information according to the random value and a public key of a first user terminal; and 
 
 transmit the encrypted information and the second proxy relationship. 
 
     
     
       8. The user terminal according to  claim 7 , wherein the processor is further configured to:
 select, by the user terminal, a symmetric key, and encrypt the original information according to the symmetric key to obtain an initial ciphertext; and 
 encrypt the symmetric key according to the random value and the public key of the first user terminal to obtain encrypted key information, wherein 
 the encrypted information comprises the initial ciphertext and the encrypted key information. 
 
     
     
       9. A system for performing proxy transformation, comprising:
 at least one user terminal, configured to establish proxy relationships between the user terminal and other user terminals at a first user terminal, and generate a proxy relationship library according to the proxy relationships; and 
 a server, wherein 
 the first user terminal is configured to select a first proxy relationship between a target user terminal and the first user terminal from the proxy relationship library, then select a random value, and generate a second proxy relationship according to the random value and the first proxy relationship; 
 the first user terminal is configured to encrypt original information according to a public key of the first user terminal and the random value to obtain encrypted information, and transmit the encrypted information and the second proxy relationship to the server; 
 the server is configured to perform proxy transformation on the encrypted information according to the second proxy relationship to obtain transformed information, and transmit the transformed information to the target user terminal; and 
 the target user terminal is configured to decrypt the transformed information to obtain the original information. 
 
     
     
       10. An apparatus comprising
 a user terminal for performing proxy transformation configured to select a first proxy relationship between the user terminal and a target user terminal from a proxy relationship library, and generate a second proxy relationship according to a random value and the first proxy relationship, configured to, according to the random value and a public key of a first user terminal, encrypt original information to obtain encrypted information, and configured to transmit the encrypted information and the second proxy relationship.